Your messages are quite old and I'm not certain you are still on genealogy.com. I am doing research into American families that lived in Pau.
I believe Armand Lachaise was married to Caroline Mathilda Thorne. She was the maternal aunt of Mrs. Frank Lawrance (Francis Cooper Lawrance, wife Frances Adelaide Garner. Her brother was William Thorne Garner, who died in the famous Mohawk boating accident on July 20, 1876. The William Garner you refer to in your posts is completely different than this one. I have several articles about William Thorne Garner.
I also have a copy of the birth certificate for Leon di Moltke-Huitfeldt.
If you would like to exchange information, please send me your e-mail address.
I am interested in any new information you might have about the laChaise family. I'm also interested in the Moltke-Huitfeldts. If you have any new information about William Thorne Garner's father Thomas Garner, I am interested in that too.