Thanks India Four Two, of course ! It's a long time since I last flew in the USA, too long evidently. Doing that downwind 45 degree standard join you describe would have allowed the 340 to see the circuit traffic, and them to see him.
It;s hard to see what the 152 pilot could have done safely, other than an orbit on base, which is not normal practice for students as far as I know. Doing a go around from base leg meant crossing the path of a fast moving machine - far from ideal., and would likely have led to the same outcome, without good luck. Not nice.