Put out a bird cage, sized for parakeets or cockatiels (garage sale find?), and fill some dishes in it with lovebird seed mix and a dish of water. tie the door open with a twist tie, and put the cage in your yard where you can see it from your window. Toss a bit of seed every couple of days around the cage to get birds to come investigate.

Assuming he was previously owned, the lovebird won't be as fearful of entering the cage as true wild birds are, and if you see him in there, walk outside quickly and calmly, talking soothingly, and block the door with your hand as you undo the twist tie and close the door. Hopefully you will do this quietly and quickly and he won't know enough to flee out the little door before you can close it.