Try plugging the receiver into the eArc hdmi input. On my setup, everything that's plugged into the tv goes through the receiver and I don't have to switch inputs on the TV. It also frees up other inputs on the receiver.
So, I've routed the cable box to the TV, but I'm not sure how to get sound from the TV to the surround sound receiver. The HDMI from the eArc to the receiver isn't sending sound to it. Isn't it an "In" port rather than out?