Tire Rack has an optional size for the TLX SH-AWD of 245/40/19. They don't mention any other options.
Honda 19" HFP wheels are 8.5's. I actually just confirmed that I had 255/40/19's on them which fit my 2014 Accord touring perfectly (drove on them for a year fine). Shouldn't have any issue with the TLX.Wow, that's pretty wide. How wide are your 19" wheels?