Seems like the changes to the Blockchain should be wrapped up by August 02, or shortly thereafter, with some exchanges matching the Bitcoin balances held in users wallets, while other exchanges are not participating in the split.

Some of the exchanges that are offering a match of BCH for BTC in wallets, according to their statements, are the Bitfinex, Livecoin, and Yobit exchanges.

Check out the blog from LiveCoin