This sound started about 5 month ago and once i noticed it everytime im turning steering wheel and now its getting anoying... i own this car for 2 years and this sound was absent. have you noticed similar sounds with your lexuses? i might remove steering wheel to see if it needs lubrications or whats going on there.
PS. Maintenance warning light is lit coz i have to change oil and filter soon.

See the video here:

 

Just out of curiosity, if you can make the noise while the vehicle is stationary and running, if you put your head by the brake pedal and turn the wheel, do you hear the noise?
I'm wondering if the noise is occurring at the base of the steering column, but just traveling up the column to the wheel.

And if you can't duplicate it with the vehicle parked, then I don't think it's actually coming from the steering wheel area...I would guess at the bottom of the column.