Cortisol and T are normally higher in the morning. Example: when people are prescribed a gel they are instructed to apply it in the morning to emulate more natural production.
Read this on cortisol and resistance training:
http://www.ncbi.nlm.nih.gov/pubmed/20560706
And this on cortisol, T and training all play together. Pay attention to the effect CHO has:
http://www.ncbi.nlm.nih.gov/pubmed/11905937
hope it helps,
kel