I learnt alot from this thread. Pilots from all over the world contributed their insight. Resting the elbow on the armrest results in smooth flying. However some pilots dont like to use the armrest. So finally the conclusion . Using the armrest or not should allways be the personal choice of the pilot.
However when handflying Airbus From A318 onwards upto A380 every pilot must use the outboard armrest. I am sure the same will apply to to Canadair C series and Sukhoi regional jetlier and Falcon 7x.
Thank you Gentlemen for your participating.
Ravi