Hello,
I spent some time yesterday researching your question concerning Joseph Lacelle, son of Benjamin Lacelle and Olive Demers. I was not able to find his marriage, but in the process of researching, I found quite a few other items that, if you have not already found them, might be of interest to you.
Benjamin Lacelle, son of Antoine Lacelle and Adelaide Lebrun, married Olive Demers on 31 Jul 1865 at St-Benoit. This was her second marriage - she was previously married to David Lacelle. David Lacelle, son of Luc Lacelle and Louise Locbrune married Olive Demers, daughter of Isidore Demers and Esther Prezeau on 19 May 1851, at St. Benoit.
I find this family on the 1881 Census in the Wentworth-Montcalm district of Argenteuil: Benjamin Lacell, age 46
Olive Lacell, 46
Perpetué, age 15
Melina, age 12
Selena, age 9 (Marie Célina, born 24 Dec 1871, St-Benoit.)
Joseph, age 5
"Olglantine", age 3
Perpetué Lacelle (daughter of Benjamin Lacelle and Olive Demers) married Léon Auger on 19 May 1884 at Basilique Notre-Dame, Montéal. Léon was the son of Léon Auger and Marie Paquet.
Emelina Lacelle (daughter of Benjamin Lacelle and Olive Demers) married Pierre-Zotique Tassé, son of Theodore Tassé and Mathilde Rochon, on 25 Jul 1887 at Notre-Dame-des-Nations, Montfort, Argenteuil.
Eglantine Lacelle (daughter of Benjamin Lacelle and Olive Demers) married Martial Lauzon (son of Joseph Lauzon and Adelaide Laroche) on 27 Aug 1900 at St-Philippe-d'Argenteuil. Eglantine is listed as the daughter of Benjamin Lacelle and the late Olive Demers of St-Michel parish.
In 1901, Joseph Lacelle is still living with his father Benjamin in Wentworth, Argenteuil. Benjamin is listed as born in Jun 1835 and Joseph on 19 Aug 1876. As you know, of course, Joseph was really born 11 Aug 1875 and baptized on 12 Aug 1875 at St-Benoit.
If Joseph Lacelle happened to have been married at St-Michel-de-Wentworth, that marriage won't be listed on Ancestry because the listing of vital records for St-Michel-de-Wentworth skips from the year 1892 to the year 1913.
Do you know whether Joseph Lacelle and his wife moved to Ontario, as did Cyrille Patrie and his wife Celina Lacelle? Do you know when/where Joseph Lacelle died?
I can research a bit more if you can provide any other clues.
Margaret