Problem with converting accented characters to uppercase

The command \uppercase does not work properly with certain accented characters, like the Hungarian ő or ű or such characters as ł, đ and ć. If I type the characters like \H{o}, it works, but I'd like to type it directly as ő, as it's used multiple times.Could you suggest a workaround?

\documentclass{article}\usepackage{t1enc}\usepackage[utf8]{inputenc}\begin{document}\uppercase{árvízt\H{u}űr\H{o}ő tükörfúrógép đdłlćc}\end{document}