May I ask where did you come up with his birth date of 1847.
Elphege Arcadius Riche b. Jan. 18, 1856 in Avoyelles Parish, La. s/o Elphege Arcadius Riche & Helene Lemoine. A phone call to St. Paul's Catholic Church is all that is needed to acquire a baptismal record. Give them this information: Bapt. bk. 6 & & 1850-1872 p. 125.