Part 44 in Tony's Radio Reviews:
Lost Horizon: A superb show, one of his best, and in some ways preferable to the movie, which I adore. Welles plays the Dali Lama, and for once he's just right. The rest of the cast is perfection, the script is tight and effective and Herrmann's music and the sound effects are cinema quality. It's just a perfect show, and interestingly the very first Campbell Playhouse,so it's got a long intro by the announcer about Welles, and it's hilarious when he keeps saying the events of Welles' life are too well-known to go into, but then goes into them anyways.
Available via internet on cd via www.crabapplesound.com in excellent sound. (Check to see that they have an encrypted order page!)