The sought-after striker made his first impact of the campaign with a hat-trick in Nancy last weekend, and he proved clinical twice from 12 yards against Caen to hand the hosts back-to-back wins.
Lyon began on the front foot and Corentin Tolisso tested Remy Vercoutre with a header before Lacazette had a penalty claim waved away after tumbling under an Alaeddine Yahia challenge.
Lacazette continued to cause Caen problems and only the close attentions of Emmanuel Imorou prevented him nodding home Rafael's near-post flick.
But, with half-an-hour played, the France international was gifted the perfect opportunity to open his account for the evening when Ivan Santini handled inside the area.
And he needed no second invitation, confidently striking home the spot-kick to hand Lyon a half-time lead.
Caen almost grabbed an unlikely leveller just after the restart when Yann Karamoh showed some neat footwork to carve out a shooting opportunity but his stinging effort grazed the bar with Anthony Lopes well beaten.
The visitors refused to lie down and both Ronny Rodelin and Yahia wasted decent opportunities to test Lopes as frustrated Caen boss Patrice Garande looked on.
But, deep in added time, Lyon wrapped up the points when Lacazette netted his second penalty of the night after Jordan Ferri went down under a Syam Ben Youssef challenge.
