In theory, lobsters could live forever. In the wild they usually die during their ecdysis. During the ecdysis, lobsters can not ‘breeze’. As their exoskeleton becomes thicker with age, the ecdysis takes longer until a lethal duration is reached.

From the German Wikipedia article:

Lobsters become more fertile and stronger the older they get, not the other way round. The key to this is probably telomerase, which is able to rejuvenate their cells indefinitely: Lobsters produce sufficient amounts of this substance to renew their telomeres and prevent cells from dying. This mechanism is so effective that animals that are 60 or 70 years old are just as fertile as those that are several decades younger.