I didn't know if you had the birth record for Isabella so here is the info.
Quebec, Vital and Church Records (Drouin Collection), 1621-1967 about Isabella Margaret Carson Name: Isabella Margaret Carson Event Year: 1900 Event: Naissance (Birth) Religion: Presbyterian Place of Worship or Institution: Cushing (Presbyterian Church) Province: Québec
It says: Isabella Margaret Carson, daughter of James Ezekiel Carson of the village of Stonefield, in the township of Chatham and county of Argenteuil and Emma Elizabeth McMillan, his wife, was born on the 16th day of May, 1899, and was baptized on this the 18th day of October 1900 by me, James Fraser.
******************** You mention her in 1911 census but not 1901 so in case you don't have that here it is.
1901CHATHAM, ARGENTEUIL, QUEBEC CARSON James, age 35, labourer, born August 10, 1865 Quebec
Emma, age 38, wife, born Nov. 16, 1862 Quebec
Fraser, age 3, son, born August 17, 1897 Quebec
Bella, age 1,daughter, born May 16, 1899
********** Her brother James Fraser Carson's baptisms in in records as well - let me know if you want the info.
I see that in 1911 their surname is spelled Orison in index. This reminded me to look for odd spellings of her name for a marriage so I tried just using her first name and first name Joseph for husband but still cannot find them.
I have not yet found the marriage you want, but I did find a marriage for James and Emma - they were married in Ontario
Ontario, Canada Marriages, 1801-1928 about Ezekiel James Carson Name: Ezekiel James Carson Birth Place: Point Fortune Pq Age: 28 Estimated Birth Year: abt 1868 Father Name: John Carson Mother Name: Lusinda Carson Spouse Name: Emma Mcmillan Spouse's Age: 30 Spouse Birth Place: Geonville P Quebec Spouse Father Name: Duncan Mcmillan Spouse Mother Name: Harriet Mcmillan Marriage Date: 4 Mar 1896 Marriage County or District:
Do you have an approximate birth year and place for Joseph? It might help to find them.