Lightweight or SPV clients like Electrum and MultiBit (but
stop using MultiBit ASAP if you currently use that) don't enforce network rules or validate transactions and merely follow the longest chain. So if, in the
infinitesimally unlikely event, BCC
did somehow manage to build the longest chain, Electrum users would
only be able to access BCC and not their normal bitcoins (unless they export/import their keys). It often surprises me that not everyone realises SPV clients work like this.
However, in the far, far more likely event that BCC doesn't build the longest chain,
the only way Electrum users can access BCC is to export their keys and import them to another client supporting BCC //DOUBLE EDIT: The method
arwani1985 posted below is almost certainly easier and doesn't involve messing about with keys, do that instead and just use the rest of this post as a guide for exporting keys for backup purposes.
(and as the OP has mentioned, select your software carefully as there are wallet clients which could potentially have been created to take advantage of unsuspecting users, we don't know how legitimate these new wallets are yet). There are indeed some security risks involved when handling the private keys directly, which is why your wallet software doesn't normally store them in that raw format. Make sure your PC, or whatever device you're using, is 100% clear of spyware or keylogging malware before you export your keys. It's also generally suggested to do it whilst disconnected from the internet, just in case.
From the menu, it's: Wallet -> Private Keys -> Export -> *enter password*
Once you're done importing them to the new wallet client, don't leave the private keys lying around, unless they're stored securely somewhere offline as a passworded backup, which is actually recommended. Your device could get infected in future, so you don't want attackers gaining access to your keys just sitting there in the open.
You can do all of this at any point after the fork if you choose. You only have to download the blockchain in your new client before August 1st if you're in a hurry to dump, although I'm guessing many are hoping to do just that.//EDIT: The
Electron Cash wallet appears to be the work of the forum's very own
Jonald Fyookball