Thanks for the tip and assurance. I'm trying to do this by importing my private keys from my Electrum BTC wallet to my Electrum LTC wallet, using the sweep function, restoring the wallet, etc. but it doesn't seem by working and allowing me to move forward (for example the 'sweep' button is greyed out). I must be doing something wrong, and wonder if the Electrum LTC wallet isn't recognizing the keys from the Electrum BTC wallet? Thanks again for any help!
Not sure what's wrong as I've never faced this issue, neither I'm an expert in key generation, but according to DannyHamilton (who has way more knowledge than me)
here, you really just need to export from BTC wallet and import private keys on your LTC wallet.
If you send litecoins to a bitcoin address that you control, then you will need to export the private keys from your bitcoin wallet and then import those private keys into your litecoin wallet. Then the address will be available to your litecoin wallet so that you can regain access to the litecoins.
Not sure what to suggest next. Maybe try with another client and see if you can import.