"Particles" in Japanese are actually a fairly diverse class of words. Some things which are traditionally called particles are suffixes. For instance, the representative plural marker, -tachi is very closely bound to the noun it attaches to--not even core argument case markers like =ga or =o can interrupt it.
Other things traditionally called particles, especially the non-core argument-marking case particles are clitics. This is most clearly seen based on the fact that some of them, like the genitive case marker =no, which, while not being very closely attached to the noun it modifies, it still has some phonological influence. For example, words where accent falls on the last mora, like hashí LH(L) 'bridge' become accentless when =no is added: hashi=no LHH. Compare this with what happens when you add the case marker =ga: hashí=ga LHL--we see the expected pattern for a final-mora accented, two mora word.
Yet other things are postpositions. Here I'm thinking specifically of sentence-final particles like yo. These clearly don't attach to individual words, but instead to phrases or entire sentences (depending on their scope). They are prosodically independent, have some semantic independence, but are still somewhat "stuck" onto the phrase they modify.
Still other things are likely entirely separate words which happen to be one or two morae long, and thus just happened to be analyzed traditionally as particles. Here I'm specifically thinking of things like the na in so-called na adjectives (or adjectival nominals, if you prefer), which is actually one of the attributive forms of the copula no, itself a defective verb.
So what about these honorifics you can stick at the beginning of a word? I'd just call them prefixes. They are very closely bound. When an accented noun (of any kind) takes the prefix o-, it becomes accentless. So, for instance, intially-accented íkutsu HLLL 'how many?' becomes o-ikutsu LHHH. Similarly, iwái LHL 'congratulations', which has its second mora accented, becomes o-iwai LHHH. And so on. Even outside of a more rigorous linguistic analysis, such as under the traditional Japanese system of traditional grammatical analysis, to the best of my knowledge, these are not called particles (助詞 joshi), but rather prefixes (接頭語 settoogo).