[1] Lonsdale was the daughter of John Gylby, canon of Lichfield and Sarah Martineau, née Jardine.

A vocal anti-suffragist, Lonsdale's name appeared on the list of signatories to "A Woman's Protest Against Female Suffrage" published in The Nineteenth Century in 1889.

[4] Lonsdale was an early organizing member of the Women's National Anti-Suffrage League and part of the group's executive committee together with Mary Ward.

[5] Her letter published in The Times in 1907 encouraged readers to sign a petition against the woman's vote, which was presented to Parliament after collecting 37,000 signatures.

[9] She wrote the Introduction to The Slippery Slope, and Other Papers on Social Subjects by William Amias Bailward, published in 1920.