If you read MSDN documentation for LSA_OBJECT_ATTRIBUTES you will think it’s defined in LsaLookup.h:

MSDN

And that it’s supported since Windows 2000 but I couldn’t find it in this header file.

Instead I found it in NTSecAPI.h, so I decided to check the different SDK versions and starting from SDK v7 LsaLookup.h exists but in earlier SDK’s (v5.0, v6.0a and v6.1) there is no LsaLookup.h.