I was able to figure out which one of the several connections there was leaking because with the LPG control switched off there was no smell at all and with it switched on there was. All but one of those connections is upstream of that control, therefore the downstream one was the culprit.
We're defrosting the plate on the frigibar tonight. Hopefully the ice will be all melted by morning.
One bummer-- the propane cylinders that came with Lark are apparently under recall, and the company that made them is gone. So I guess we're in the market for new cylinders.