Tina,
You're right that pool temperature is important. I should have said that we found a good indoor swim school that keeps the pool at a very warm temperature. That's definitely an important factor! Good point.
I also didn't mean to imply that swimming lessons will give more therapy than an actual therapist. I just meant that if you can't find an aquatherapist (which is the case for some), it's not necessarily cause for panic. A mom or dad swimming with the child and moving that arm around - in a warm pool! - is a good secondary alternative.
Janet