the transaction will not be stored anywhere unless it is broadcast. and since you have been offline you did not broadcast it so it does not exist anywhere including in your wallet file.
here is your wallet location: http://docs.electrum.org/en/latest/faq.html#where-is-my-wallet-file-located
it stores your transactions. if you want to make sure, open it in a text editor but make sure not to change anything to make it invalid!