In a blender combine all except the sour cream and oil. Turn on and finely puree the whole. In the running machine the oil, first leisurely, then in a continuous stream until the whole is properly emulsified.
Just like a sauce mayo.
Transfer to a suitable container and add the sour cream. Season with salt and pepper. Store in a cool place. Keeps for a week properly refrigerated at 7 C without any problems.
Excellent ditto as a dip and for eggs.
Tip: Always use organic lemons for cooking, if possible!