early on yesterday

[joham]

Randy Pausch set the tone early on yesterday at his farewell lecture at Carnegie Mellon University.

In this sentence does 'early on yesterday' equal 'early yesterday'? Or 'early on' has nothing to do with 'yesterday'?

Might I ask native English teachers to help me? Thank you very much.

[2006]

Randy Pausch set the tone early on yesterday at his farewell lecture at Carnegie Mellon University.

In this sentence does 'early on yesterday' equal 'early yesterday'? No. Or 'early on' has nothing to do with 'yesterday'? That's correct. It means 'early in his lecture'. The sentence could be rewritten as 'Randy Pausch set the tone early on in his farewell lecture yesterday at Carnegie Mellon University.'

Of course the lecture might have been given in the afternoon or evening.
Might I ask native English teachers to help me? Thank you very much.

2006