Cazorla, the instigator of many Arsenal attacks, clipped in a great finish from the edge of the area in the 48th after being picked out by Gervinho, who then led a counter-attack in the 68th and passed for Giroud to drill home low to make it 3-0.
Robson-Kanu stooped to head in a cross from the left a minute later, with Arsenal left back Nacho Monreal having to go off after injuring his knee in the build-up to the goal.
But Arteta ensured there were no late anxieties for the hosts by calmly stroking in a penalty after Alex Oxlade-Chamberlain was fouled.
"We played with good collective spirit, technical quality and always went forward," Wenger said. "We created many chances, that's the most pleasant thing. We defended well, had good discipline and didn't become easy when the game became easy."
Arsenal is four points behind third-place Tottenham with a game in hand.