Good news (I think). Had "sneezy" to the vet earlier this week and everything seems to be fine. Vet listened to heart and lungs, checked glands, tonsils, ears, etc. Could not find anything that would have caused the episodes. Additionally, he has not had any more episodes since Saturday. For now it remains a mystery, but thanks to your alerts, if it occurs again I will not hesitate to get him in to see the vet right away.