Regarding the linked blog page: It's a nice introduction to the idea of cases, but it's not entirely accurate: the usual dative/locative form of Pavel is Pavlov

Regarding the linked blog page: It's a nice introduction to the idea of cases, but it's not entirely accurate: the usual dative/locative form of Pavel is Pavlovi. Pavlu would be used only when there's a surname present. Thus "o Pavlovi" but "o Pavlu Novákovi".