OP has made it by taking your suggestion. Kudos. But why it has to be online to make it work?
If there is no connection to the internet, it's not possible for electrum to get synced to the blockchain and it wouldn't have any information about the transactions already made.
Take note that even if you want to make a transaction offline in electrum, you need an online device too. The online device is required for getting UTXOs data and broadcasting the tranaction.