I've had this Peace Lilly for at least 10 years and it used to be the (small) joy in my home life. Often it would bloom a few of it's wonderful white "flowers". However, it hasn't done so in at least 5 year....until now. I've got ONE.

What can I do for this otherwise healthy guy to make him bloom more often?

The otherwise healthy guy never blooms. What can I do to make him bloom more often?