Someone who screened the film (maybe for one of the film festivals) posted this brief review on IMDb:

And it's a good biopic, not exceptional, but hey, we have lots of biopics every year.

Christopher Plummer and Helen Mirren are perfect. Explosive, excellent, magnificent. Their love story turns into madness at the end of Tolstoi's career.

James McAvoy and Anne Marie Duff have less screen time, but they're also nice supporting roles.

I loved the ending scene. Was amazing.

The score and the production (cinematography, art direction, costumes, makeup, music) is wonderful, same as Christopher and Helen. I can see them getting BEST ACTOR and BEST ACTRESS nominations.

We'll see if we can get more info out of him/her.

Toronto announced their complete lineup on Thursday, and TLS was not listed. Also, looks like San Sebastian released what some are calling their full lineup and didn't see TLS listed. If the film is seen as "a good biopic, not exceptional," that may explain it.