I don't think LH has a flight to LPA. If you saw one it's probably a codeshare with Spanair (JK). Generally flights to the Canary Islands are insanely overbooked over the summer. If I was you I would take a MAD-LPA ticket, but also a couple of backups (MAD-AGP-LPA, MAD-SCQ-LPA, MAD-BCN-LPA). Since very destination in Spain except the Canary Islands is Zone 1 from MAD, you should only need a Zone 1 ticket and a Zone 3 ticket (for the Spain-Canary Islands leg). If you don't use the Zone 1 pass you can always refund it.

Check your company's level of agreement with IB, JK and UX, those are the airlines that fly MAD-LPA. I can check loads on JK if you need.

brgds