Some way to install libborqt_6.9.0-3_i386.deb, once downloaded?

[Erik Christiansen]

apt-get install works fine for me, for packages available in the
repositories.

Unfortunately, the only copy of libborqt_6.9.0-3_i386.deb that I've
found so far, is on an http/ftp mirror. After downloading the file, I
put it into /var/cache/apt/archives/, hoping that apt would be able to
read from its archive, not just write to it. ;-)

Maybe I'm not holding my mouth right, but neither

apt-get install libborqt_6.9.0-3_i386
                                           nor
dpkg -i libborqt_6.9.0-3_i386

do the simple job required.

I'm fervently hoping that there's some direct way to install a package
that one has e.g. received by email, or self-generated?

Erik