After being named Substitute of the regent of the Sacred Apostolic Penitentiary on 5 February 1910, Lauri was raised to the rank of Domestic Prelate of His Holiness on 5 April of that same year.

He received his episcopal consecration the following 21 January from Cardinal Donato Sbarretti, with Archbishop Vincenzo Sardi di Rivisondoli and Bishop Americo Bevilacqua serving as co-consecrators.

Pope Pius XI created Lauri Cardinal-Priest of San Pancrazio in the consistory of 20 December 1926, ending his time as Poland's nuncio.

He travelled in procession the nine miles from Dun Laoghaire to St Mary's Pro-Cathedral in Dublin in the Lord Mayor's Coach, led by the Blue Hussars, a recently created ceremonial cavalry unit.

[4] Made a Freeman of Dublin at a ceremony at Mansion House, during his week-long stay, the Legate visited a number of towns including Armagh, Drogheda, and Dundalk.

Lauri wrote Edward Joseph Byrne, Archbishop of Dublin,I shall never forget the unforgettably glorious days of this Eucharistic Congress .