Quebec Bishops Joint Pastoral; “Purity Crusade”, Published May 5th 1946

Another full source has been found! Though unfortunately, it is in FRENCH!

It was in the footnotes from this article here. 

Archevêques et évêques de la province de Québec, « Croisade de pureté », Lettre pastorale collective, n°114, 5 mai 1946 ; paru dans : Mandements, lettres pastorales et circulaires des évêques du Québec, volume 17, 1943-1954, Chancellerie de l’archevêché, Québec, 1955, p. 241-243 ; p. 253-254 ; p. 257 ; p. 259.

Archbishops and Bishops of the Province of Quebec, “Crusade purity” Joint Pastoral Letter, No. 114, May 5, 1946; appeared in:  Mandements, pastoral letters and circulars of Quebec Bishops , Volume 17, 1943-1954, Chancellor of the Archdiocese, Quebec, 1955, p. 241 -243; p. 253 -254; p. 257  ; p.  259 .