On 7 January 1885 she married Marek Arnsztein (alternative spellings: Arnsztejn, Arnsztajn, Arnstein; 1855–1930), a physician educated in Warsaw, Vienna, Berlin, and Paris, and a political and social activist, a native of Kazimierz Dolny based in Lublin from 1884.

The opening poem, untitled but beginning with the words "O nie płacz..." (Weep thou not...; p. 7), sets the tone for the entire collection as she tries, with uncommon tenderness and filial piety, to soothe her mother's pain at having her own songs dispersed by the winds of time to the farthermost recesses of the soul: the implication is that the poems in this collection will become her mother's own, which the daughter will now sing for her, the lute in hand, sitting at her feet.

[13] The latter volume contains the poem "Z nocy bezsennych" (Out of the Sleepless Nights) dedicated to her husband, Marek Arnsztein, as well as the memorable "Wspomnienie Meranu" (A Remembrance of Merano) that evokes her travels in the Trentino-Alto Adige region of Italy, and which begins: Meran… pamiętam… nieraz dziś w zimy rozgwarze, Mroźnem tchnieniem owiana, nagle zamknę oczy, I o błogosławionej dolinie zamarzę.

Wacław Gralewski (1900–1972), a poet and prominent Lublin littérateur, cites a report (which he qualifies as uncorroborated) that Arnsztajnowa was supposed to undergo a (successful) therapy for tuberculosis at Merano, an option open only to the very rich.

Oto Dziś w imię Jutra na nas woła.Czas wzrok od grobów odwrócić pokuty!Włos otrząsając popiołem przysuty,Twardym szyszakiem nakrywamy czoła,By krzepką dłonią wśród gruzu i łomuKielnią i mieczem stawiać węgły domu.

During the First World War Arnsztajnowa (nom de guerre Ara) participated in armed struggle for the independence of Poland as a member of the secret Polish Military Organisation in Lublin (her town house in the Old Town of Lublin served as a secret archive of the POW and a hub for other organizations, such as the Union of Armed Struggle and the clandestine Polish boy scout movement; the expansive basement served as an arsenal).

Comprising five ottava rima stanzas, the 40-line poem brought her the Silver Laurel of the Polish Academy of Literature, a (now historical) body awarding the most prestigious literary honours of the land at the time.

To this period, in addition to the aforementioned collection Archanioł jutra (1924), belong also her volumes of poetry entitled Odloty ("Flying Away"; 1932),[22] a compilation of verses published in literary journals between 1902 and 1926, and the collection produced jointly with Józef Czechowicz, Stare kamienie ("Old Stones"; 1934) which was at once a tribute to her beloved Lublin, a city in which she continued to reside until 1934, epitomized in the poem "Tobie śpiewam, Lublinie" (To You do I Sing, O Lublin!

[25] Odloty represents a continuation of the modernist esthetics that dominated the first phase of Arnsztajnowa's literary life, as evidenced in the imagery employed and in the method of shaping of the lyrical persona, as well as in the return of the fairy-tale motifs favoured by the Young Poland poets, such as lakes, mirrors, and shadows.

Arnsztajnowa's dramatic works remain largely confined to manuscript, including her award-winning play Na wyżynach (Krystyna) ("On the Heights: Christina") which was staged to great acclaim in Lvov in 1899.

Her other plays which were seen on the stages of Kraków and Łódź, in addition to those of Lublin and Lvov, but which remain unpublished, are (with dates of theatre production) Na kuracji ("A Stay at a Spa"; 1894), Perkun ("Perkūnas"; 1896), and W stojącej wodzie ("In the Stagnant Water"; 1901).

[34] Her versions of Kipling's "Cities and Thrones and Powers" and "Harp Song of the Dane Women" (poems from Puck of Pook's Hill) were published separately in literary magazines.

[35] Similarly, her 1932 translation of a 12-verse excerpt from the French of Les Stances by Jean Moréas (Book 3; XII), beginning O toi qui sur mes jours de tristesse et d'épreuve Seule reluis encor... reads better than the original: O, ty, co dni mych smutkom i zmaganiom blaskiem przyświecasz wytrwałym...[36] Always respectful of and ready to honour others for their achievement in their field, in 1899 Arnsztajnowa contributed to the liber amicorum for Aleksander Świętochowski on the occasion of the 25th anniversary of his editorial work, a sumptuously produced volume that opens with her poem "Grajek" (The Fiddler; from the Poezye of 1895).

Her poem composed in tribute to the Polish geographer, Wacław Nałkowski (1851–1911), the father of the writer Zofja Nałkowska, on the occasion of the 25th anniversary of his scholarly work in January 1903, did not come to light until 55 years later, for example.

[38] Her patriotic feelings found expression in the contribution she made to the collective volume published by the Teachers' Union to commemorate the school strikes in Partitioned Poland mounted in protest against marginalization of Polish culture by the occupying powers;[39] while in 1935 Arnsztajnowa served on the editorial board of a commemorative volume for the Polish Military Organisation, to which she contributed the keynote poem (on the theme of the Unknown Soldier) serving as a motto for the publication.

After the coup d'état of May 1926, during a visit to Lublin in June 1931 of Piłsudski's figurehead president, Ignacy Mościcki, she wrote in poetic prose a fulsome welcome for him in a local newspaper ("whole streets are running out to Him with open arms while ancient city walls silvered by age reverberate with the Good News: hail Thou the visible manifestation of the Independence!

[45] After Łobodowski's protest published in the most prestigious literary journal of the interbellum epoch, the Wiadomości Literackie, Piasecki remained unrepentant, and a fresh antisemitic attack on Arnsztajnowa was printed with additional vitriol in the Prosto z mostu edition of 8 August 1937.

[51] In what is perhaps the most reliable eyewitness report, that of the poet Hanna Mortkowicz-Olczakowa (1905–1968), at the moment of her death — during the mass murder of patients at a hospital near All Saints' Church in Warsaw where she lay ill — Arnsztajnowa had two books with her, Dante's Divine Comedy and her own collection of poetry published in 1932, Odloty ("Flying Away"), on the poetics of departure.