I'm sorry to say I don't have anything on the LAWSON or LOSSING family yet... I have only just recently confirmed my ancestor is HANNAH LAWSON; and I don't believe anyone has (yet) been able to CONFIRM that LAWSON was once LOSSING... although personally, I think it is a very likely!
If I were you, I would post a "new" message to the board re: your family and hope that one of the "foremost" Lossing researchers (i.e., those that have a lot of data on the family), such as Kathy Hoeldke, will respond (or perhaps email her directly).
Also, remember when searching old records to check for ALL variations on the surname!!