Since your question has now been moved to the Catholic Nuns thread, there are a couple of messages in this thread that might be useful.
I also saw a thread on the NEHGS site, which might be useful. While it may not specifically apply in your case, the process might be helpful.
Question: How do I locate a nun with the Sisters of St. Joseph in Massachusetts? She served from 1900 through 1943 and I cannot find her in any United States census . Thank you!
Answer: The Archives for the Massachusetts Order of the Sisters of St. Joseph's can be reached online at http://www.csjboston.org/archives.htm
Archivist , Boston CSJ Archives, 637 Cambridge Street, Brighton , MA 02135 -2801
Telephone: (617) 746-2117, FAX: (617) 783-8246 , e-mail: email@example.com://www.americanancestors.org/online-genealogist/