To use ARC you need to have it in both the TV and receiver. The receiver HDMI output has to connect to the HDMI-ARC input on the TV (there will only be one marked ARC). The cable has to be an recently made HDMI cable. You may have to turn the ARC on, the TV speakers off, and change the audio output type to get it to work. You also need to select the ARC as your connection for one of the inputs on the receiver.
Lastly if you can't get it working use the optical audio output. No loss of quality.