Landscape page has different dimensions than portrait

My question is duplicate of this. How to produce landscape page the same size like a portrait one?

documentclass[a4paper, 12pt]{article}
usepackage{pdflscape}

begin{document}
    begin{landscape}
        This is what you want?  
    end{landscape} 
    No, it isn't.
end{document}

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Usage of lscape instead of pdflscape produces correct page size, but it is not rotated inside pdf document. How to do the trick?