Thanks for the question. As you probably know, we rely on the NRefactor conversion engine for our online converter. It has not been upgraded in a while (our version of NRefactor, that is), so I'll work on getting the latest version applied soon. I'm not sure if that supports LINQ conversions yet, but I'll also do some research in the SharpDev community to see what I can learn.
I'll follow-up once the engine has been upgraded.