If two or more lots or a combination of lots and portions of lots with continuous frontage in single ownership are of record at the time of passage or amendment of this Ordinance and if all or part of the lots with no buildings do not meet the requirements established for lot width and area the lands involved shall be considered to be an undivided parcel for the purposes or this Ordinance and no portion of said parcel shall be used or sold in a manner which diminishes compliance with lot width and area requirements established by this Ordinance, nor shall any division of any parcel be made which creates a lot with a width or area below the requirements of this Ordinance.