grep for string in file after a certain part of the file

[b-boy]

Hi guys

I want to search for a sting in /var/log/messages but I want to look for the work after a specified time onwards

So what I want is to look for ubuntu in /var/log/messages but only look after 10:00 anything before 10:00 must be ignored

how can i do this

[geirha]

awk '/ubuntu/ {if ($3 >= "10:00:00") print}' /var/log/messages