Are you asking because you have a cable modem that has to be connected to it by ethernet cable to provide the broadband? If so then you will have to have the router connected to this modem.
If you are getting ADSL broadband through your phone line then the router will have to be connected to that via ethernet cable so as long as there is one in the lounge, and if that is where you want the router to be, then there should be no problem. Don't forget that if it is via your phone you will need to put an ADSL filter (should be one with the router) into the phone socket and then attach your router to this. If you have any other phone extensions in the house then they should also have a filter to prevent any interference.
I don't know your PC set up but the router will also allow you to attach by ethernet cable PC's that you do not wish to be wireless.
Hope this helps.
Theoretically you should be able to receive a good wifi signal throughout the house wherever you site the router.