"Is it possible to block temporarily (enough) sunlight to a planet with stardust"?
No, I don't think so. Any nebula dense enough for that would collapse and start stellar formation in short order; that's how the Solar System itself is thought to have been born. Same goes for a cloud of gravel. Unless (as pointed out by HDE 226868) the temperature of the dust cloud was high enough to prevent a gravitational collapse.
Moreover, the solar wind pressure from the star would simply sweep away the cloud much faster than the cloud could come in, creating a planetary nebula.
Such a phenomenon can be observed in some stars that happen to enter a dense nebula. It is the case of LL Orionis, a star not much larger than the Sun, which creates a "bow wave" between 20 and 60 AU far.
- that even a planet as far as Saturn would likely be "protected" from the incoming nebula. The inner planets would never be reached and would suffer no ill effects. Actually probably no effect whatsoever, except maybe an intensifying of the harmless Gegenschein.
- that little or no gas (or particle cloud) could have a chance to enter the much more intensely sweeped area inside the planetary orbit, and block the light of the Sun. Even if released artificially exactly on the ecliptic, the radiation and solar wind pressure would blow it away.
There might still be a problem due to high energy particles being generated in the bow shock area, but I don't think that it would be comparable to a solar storm, nor that it would be likely to affect a technological civilization (or, for opposite reasons, a non-technological civilization). Actually, I suspect that biological systems would be much likelier to resist the onslaught than electronic robots.
Science stations as far as Neptune or Pluto would probably need to be abandoned, since resupply flights in the direction of the bow shock would probably be unhealthy to both ships and astronauts (it depends on technology though. Given sufficiently powerful engines, you can load sufficiently massive shielding, I guess).
With much larger (and unlikely) particles or clumps, chances are very high that many of them would experience gravitational scattering or radiation pressure braking and fall inwards at an accelerated rate, so that the solar wind would not be enough to keep them at bay. In that case the effects would not go as far as rendering the planets uninhabitable, but it could well be enough (for gravel-sized particles) to trigger a catastrophic Kessler cascade in addition to filling the sky with a continuous dazzle of falling stars. This in turn could disturb or disrupt long-range radio communications due to the radio scattering of the ionized meteoric trails.
Update: the "artificial cloud in stable disk formation" scenario is actually exactly the device of astrophysicist Sir Fred Hoyle's novel, "The Black Cloud". But even there, the dramatic turn of events is triggered by the Cloud's ability to remain stable around the Sun, which no astronomer had foreseen (rather the contrary), which in turn is caused by the Cloud's particular... nature (wouldn't want to spoil a really interesting read). A similar effect is explored in the devices supplying Larry Niven's Ringworld its days and nights. Again, stability is achieved through "innatural" means inherent in the object's composition (i.e., not something you set from the outside and let go, such as the point, speed and temperature of release of a cosmic cloud of squid ink; rather something like the ink's viscosity).