Dendobrium nobile type wintering doubt

[TER]

Hello,

I'm new to this forum and new to orchids. It's the first time I'm trying to get my nobile type Den to rebloom.

My Den sits on my balcony. During the day it gets about 16º to 19ºC (60º-65ºF) and during the night 8º-10ºC (45º-50ºF). I am watering sparcely. I have not fertilized since the beginning of september.

My question is: is it normal for it to loose leaves in the new canes? It has almost lost all the leaves on the old canes, but the lower leaves on the new 3 canes are alrealy turning yellow. The old canes are wrinkled, but the new canes are plump.

Is it a question of water, wrong temperatures or no problem at all?

Thank you for your help.