I bought a Ficus Bonsai about a year ago and it has been doing fine. Within the last few weeks though it has lost 3/4 of its leaves (they have yellowed and fallen off). I don't believe I'm over-watering it. My guess is, its the cold. (I live in a warm climate overseas but it does get chilly in the winter and there's no indoor central heating.)
Is there any thing I can do to pull my bonsai out of this? I have it under a sort of make shift heat lamp but its leaves are still yellowing.