Posted: 14/01/2016 at 22:47
As Bilje says top watering can cause leaf loss in orchids as water can pool in the crown. Always water by soaking from below ensuring no water splashes the leaves. Though the leaf loss in this case seems rather sudden for this to be the cause.
Difficult to see but the soil looks like it could be a little moist. At this time of year my orchids will usually go a fortnight between watering.
Has it been repotted? It doesn't seem to have the surface roots orchids usually have. Could be a little deep in the pot.