My current receiver is a Denon that is connected to the TV using the ARC HDMI input. It picks it up automatically anytime I turn on the TV, the Receiver turns on and it automatically plays the TV Audio. It even says TV Audio.
My old receiver is a Harmon Kardon, it does not pick up the ARC input from the TV although I did try to connect it. I have it wired using the audio output to the direct inputs and that is how I use it to interface and listen to the big speakers for the TV in the bedroom.
A friend has a newer HK receiver that does support ARC. On it there is an input select and you have to manually set it to support ARC, but once you tell it the first time that you are using ARC, it just works.
If you look at the HDMI inputs on your receiver, one of them would likely say ARC if it is supported. My Denon has one labeled for ARC and my buddies HK is also labeled for ARC.