Existence of Lindelöf Space which is not Second-Countable

Theorem
There exists at least one example of a Lindelöf space which is not also a second-countable space.

Proof
Let $T$ be the Sorgenfrey line.

From Sorgenfrey Line is Lindelöf, $T$ is a Lindelöf space.

From Sorgenfrey Line is not Second-Countable, $T$ is not a second-countable space.

Hence the result.