If I may humbly submit, the two Words for "Lord" are two differing Words:

The first "Lord" is Yĕhovah, meaning "the existing One". This Lord is the Father, the Word, and the Holy Ghost.

The second "Lord" is 'adown , meaning "master" or "sovereign". While the Word is encompassed in the first Lord, the Word made flesh--the Heir of the throne of David--is indeed referring to the Son exclusively in the second "Lord".