My grandfather was in St. Vincent's Orphans' Asylum in 1878 until his mother retrieved him in 1883. I got information about his placement from the Archdiocese of New Orleans, Archdiocean Archives.
I sorta stumbled into getting the information. I had sent in a request form with the $12 fee for the burial sacrament for my grandfather's little brother's burial and in corresponding with a nice person there, she said I might be able to get an extract from the orphanage records of their placement/discharge and that another person handled those records. I don't remember if she asked the person in that department to send the information or if I sent a form in with a fee.
You should probably ask about the charge and if you need to download and send in the request form from the Archdiocese website. There is an email address on their website. The website is:www.archdiocese-no.org/archives
Check out their website and send them an email to find out how to proceed. I am sure you will need the name of the orphan and probably the time or at least close to time, but they can tell you more about what they require.
I was sent a letter with an extract from St. Vincent Admissions and Discharges, 1858-1901, giving me the information I needed to prove the family story that grandpa was indeed in the orphanage when he was about 4 years old.
Doris (aka wendygirl)