Maybe. Maybe not.
Just realized this today.
Imagine this, trainer 1 sends out Slowpoke, trainer 2 Shellder. Trainer 1 orders Slowpoke to use Tail Whip, trainer 2 orders Shellder to Bite. Shellder bites onto Slowpoke's tail, and the Slowpoke evolves into Slowbro. Trainer 2 has lost their Shellder, trainer 1 now has a Slowbro. What happens with the match?