I was able to find some info on Joseph Cormier. First of all, I found his death record which told me the following:
 He died 1/6/1942 in Rayne
 His age was 39 [bn ca 1902]
 He was born in Acadia Parish
 He was married
 His wife was Ellis Creaeur [obviously misspelled]
 His father was Lovis Cormier [figured it sb Louis]
 His mother was Lapare Doucette [misspelled]
The State Archives in Baton Rouge has this death certificate and a copy can be had for $5.00. [Vol 500, page 4].
I found Joseph & Elise on the 1930 Calcasieu Parish census.
Joseph Cormier 27
I then found that "Lovis" was actually Louis and I found him on the 1910 census in Acadia Parish.
Louis Cormier 60 widower
Pearl Doucet 30
Ella 1 year 3 months
Then I found the 1900 census for Acadia Parish. Joseph would not have been born yet.
Louis Cormier 48
LaPearle 28 single, 2 kids, listed as a "concubine"
Evidently Moise was a child from a previous marriage and Louis had two children with LaPearle without being married. Joseph would would have been her son, too.
I was not able to find Joseph on the 1920 census when he would have been about 17 or 18. I did find Louis, his father, in Acadia Parish.
Louis Cormier 69
Lapearl 45 [listed as wife, but I did not find a marriage]
Louis Cormier died 6/27/1920 at age 70. His certificate is at the Archives [vol 13/page 5862]. His parents may or may not be listed on the certificate.
Elise was listed on Joseph's death certificate as Credeur. I don't know where exactly the couple married since they were living in Calcasieu Parish in 1930. However, in Acadia Parish I found a marriage for a Jospeh Cormier and an Elice Coruthers on 6/23/1921 [#11018]. The time period is about right, but her last name is not. Could her last name have been Coruthers rather than Credeur? Or, was this a mistake? Or, is this a different couple? I don't know. Do you know for sure that Credeur was her name?
I hope this helps with your research.