It is quite usual for MOs to have many different contributions, but if MO corresponds to some lone pair, leading impact will still be from orbitals of some particular atom. You may try to visualize HOMO and look at  it, may be you will get an idea, where it is localized.

Thank You Oleg Gromov for your valuable suggestion .

Dear, Pai

First, you can look at the components of HOMO and LUMO, and then will know  which atoms contribute to they. Of course, you can also check the the shell contribution of each atom so that to further understanding the lone pairs. 

Good Luck

Dear Yong Gao

Thank You for your suggestion. I have already found out the shell contribution of each atom. The question still remain same. Should I check the energy of lone pair in NBO analysis ?

Dear Shiv Pal,

You don't need to check the energy of lone pair in NBO.

 if it is true that “HOMO is basically composed of lone pairs of these atoms”, the shell contributions of each atom represent the lone pair electrons.

In addition, you have to look at the shape of HOMO and LUMO so that confirm what I said above.

I hope to help you

Good Luck