Using the package manager, search for qt4 and then select the desired qt4 packages. The packages selected on my system are
libqt4-core
libqt4-dev
libqt4-gui
qt4-designer
qt4-dev-tools
qt4-doc
After the installatin is complete, you may have to reset the default versions of Qt tools qmake, assistant, designer, and moc to the Qt4 versions. This is done by opening a shell and executing the commands
sudo update-alternatives --config designer
sudo update-alternatives --config qmake
sudo update-alternatives --config moc
One selects the versions one wants for defaults (e.g. the Qt4 versions). To verify that you have the correct versions, execute qmake -v and it should indicate that you are now using the Qt4 version.