It's listed as unknown in TGT but there's a reference to an LH Inn on this page:
http://community.michiana.org/mhs55/45th%20Reunion%20Speech.htm

Maybe it can be attributed to somewhere in Mishawaka, Indiana.

And another here:
http://www.mishawaka-alumni.com/memories.html

Another possibility... Could it stand for Lighthouse Inn? Not much help but it's all I found