It's true that the lending amount of a bank is heavily constrained by regulatory requirements. But that doesn't mean that banks are not lending your deposited money to someone else.

Consider two banks in the same country, so having to comply with the same reserve requirements. The reserve requirements are defined as a percentage of the amount on the banks's deposit account at the central bank. So the bank which can transfer an extra deposit to this acount is the one which is able to lend more money.