some sort of den-phal?

[ben]

I purchased this several months ago and was curious to know more specifically what it was.

I would sure appreciate any attempts at IDing this as well as any input on care for it (I might be doing something wrong). This one also has to new shoots or canes coming up but no other spikes yet. It has also had two of the leaves near the middle turn yellow and fall off plus there is one now at the top that seems to be developing a hole...?

FYI, I am keeping it near an east window and water it about once a week. I basically water it until i is running out the bottom and don't water again until it is fairly dry. It is in an orchid mix with rock gravel at the bottom for drainage.