whereuponwhere‧u‧pon /ˌweərəˈpɒn $ ˈwerəpɑːn, -pɒːn/ conjunction 
formal used when something happens immediately after something else, or as a result of something happening: 
She refused to hand over her money, whereupon there was a fight.
formal used when something happens immediately after something else, or as a result of something happening: She refused to hand over her money, whereupon there was a fight.