How does rotation for cards work? Are cards from the current cycle the only ones that are tournament legal? I am new to the game (got the core set for christmas), and I can't find any information about this online.
Cycles and rotation
There hasn't been a rotation yet. LCGs rotation was just announced as an upcoming feature of organized play at worlds 2014. Nothing rotates until there is 8th cycle released. Core and deluxe never rotate.