A state judge has blocked Warner Communication Inc.'s $1.18 billion acquisition of Lorimar Telepictures Corp., ruling that the merger violates terms of a 1984 agreement between Warner and its largest shareholder. Warner said today that it planned to appeal the decision. The ruling handed down Tuesday by New York Supreme Court Judge Walter Schackman was a victory for Chris-Craft Industries Inc., a broadcasting and manufacturing company that controls 23 percent of Warner's voting stock. Chris-Craft claimed in a suit filed in July that since Lorimar owned six television stations the acquisition violated a four-year agreement prohibiting Warner from owning any TV station so long as Warner owned 25 percent or more of Chris-Craft's BHC Inc. broadcasting subsidiary. Warner acquired a 42.5 percent stake in BHC in exchange for Chris-Craft getting the 23 percent interest in Warner's voting stock. In his 13-page decision, Schackman said that ``as a matter of law the pending acquisition of Lorimar by Warner will be a breach of the shareholders agreement.'' Schackman said Warner could not acquire any Lorimar stock until the televison stations were sold or it reduced its stake in BHC. Since the Chris-Craft suit three Lorimar television stations have been sold and Warner reportedly is negotiating the sale of one of the remaining three.