I don't know how pedantic you're intending to be here; what do you consider a "campaign contribution". If you use the traditional definition of a "campaign contribution", that is, money given to the candidate to be spent on election campaigns, then this is completely false; lobbyists cannot give any more money to campaigns than regular people can.
The power of large lobbies is more closely related to the fact that they represent a large number of constituents who donate and vote (approximately) as a block.
The power of large lobbies is more closely related to the fact that they represent a large number of constituents who donate and vote (approximately) as a block.