You are in fact lucky to have booked these flights through expedia. As opposed to LH, they do not charge anything for this. Whatever they get from LH they will refund to you. If done directly with LH, they charge a service fee which is deducted from the amount to be refunded.

I had this case a couple of time and since I realized that with expedia you save up to 45E in case of cancellation of a non refundable ticket, I often book with expedia if I am not sure about my plans.

Just call them (even before the flight) and they will refund within a week or so. No drama whatsoever!