I read that they are somehow hardy but couldn't find *how* hardy.
I have one but as I live in Brazil.it stays outdoors full time.
Some links:
The Loropetalum is a stunning bonsai which exhibits rich purple foliage and striking hot -pink flowers usually during summer months. The loropetalum is a member of the witch-hazel family and […]
www.bonsaidirect.co.uk
"Location
Frequently sold as an indoor bonsai, we would suggest that it is kept outdoors. Loropetalum seem to prefer a semi-shaded position. Full sun seems to encourage leave loss in Loropetalum bonsai."