One must collect bags when they enter the United States, so take your tags off when you collect them in LAX, exit security with your bags, and go to your airline to recheck them.

There are a few potential hiccups however... the carrier is not obligated to fly you on this specific route, so you may end up being routed via a different city. Either due to mechanical or irrops.

Also, if your bags don't make it on the flight for some reason, they will be routed to the final destination you're booked to [YVR].