Bozeman Gardeners – Know Anything About Peace Lillies?

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?