Font-lock in .log file

[Will]

Hi,

i'd like to highlight lines containing "Error:" in red and
lines containing "Note:" in blue every time a xxx.log file is opened or 
a xxx.log buffer is reverted from a file.

Currently I am using the functions
(highlight-lines-matching-regexp "ERROR:" 'hi-red-b)
(highlight-lines-matching-regexp "NOTE:" 'hi-blue-b)
but I don't know to what hook I should add them.

Does anybody have an idea?

Thanks for help in advance,

Will