Some perennials (Oriental poppies and tall bearded iris come to mind) have a dormant period after they finish blooming in the summer. But I honestly don't know if lupines are some that do.
I wouldn't give up on the plant just yet, even if all the leaves die down. You may be surprised later in the summer by a whole new flush of leaves. Just hide it away where it will get a little water, and wait. (did we talk about learning patience along with gardening a while back??
)
These are the kind of plants you need to interplant with another type that blooms later, like maybe daylilies, so that they will hide the dormant guys while they nap.
