The first clue that I found was on Interment.net. I found a listing for a "Wisner, Lawearce, b. 1870, d. 1939, age: 69yr, Plot #4.071" in the Woodbridge Masonic Cemetery. That looked promising because Lawrence was born in 1870, and I estimated that he died sometime late in the 1930s. Lawearce was obviously a misspelling, so I added that grave info on Find-A-Grave.com and requested a photo. The photo that came back was this one:
Well, that didn't help that much. Lawrence was misspelled again as Lawrance, and his middle initial was Q! Not only that, but his wife wasn't buried next to him (Martha C Morey) so I couldn't confirm his grave with hers. At this point even though the name was set in stone wrong, I believed that this was the right grave. There aren't very many Lawrence Wisners that lived in Lodi and were born in 1870 and died in the end of the 1930s.
So on a family trip as we were passing through Stockton, I stopped in at the County Clerk's office and got a copy of Lawrence's death certificate and was able to confirm that that was the right grave. On the death certificate it gives of course his death date, but also that he was buried in Woodbridge Masonic Cemetery. It didn't help me with finding out where his wife was buried, but fortunately I was able to figure that out later.