Plain and simple, whenever you are ready. In a professional setting, if you don't feel comfortable coming out, then don't. You should never feel pressured when people start asking about your sexual orientation or if you are in a relationship, or anything along those lines.
The work environment is one in which you should be very careful to separate your personal life and your professional work life.
out at work
Different companies/organizations/groups/etc.. have the general HR policy that they will not discriminate because of age, sex, gender, sexual orientation, background, etc etc... but you know what? People still do. It's just human nature. There is no such thing as a perfect work environment, just like there is no such thing as the perfect job, or the "perfect ____". I just want to be extra cautious with this post, because you never know what will happen when people know personal details about yourself that you don't feel comfortable telling them. You got to look out for your own safely, in case there are "closet haters" that you don't know about at work. If co-workers have asked you before, and you feel comfortable with your colleagues enough to share personal details, then sure go ahead and tell them. However, if you are not, beware of gossip as pictured below:
Water Cooler Gossip
Of course there are also positive aspects of coming at to colleagues. In some circumstances, you work long hours or in such close quarters with your co-workers that you become really good friends too. In any situation, you have to gauge how comfortable you are trusting other people. By all means, if your relationship with colleagues has evolved to one in which it is more of a friendship than purely "office" or "work" relationships [platonic], just go for it.
I've found that coming out to people at work who are also H6, or who are obviously open-minded individuals that you trust is also a very liberating experience. I never felt comfortable telling my direct manager or upper leadership or any of those "boss" type levels about my sexual orientation, except for the ones that are also H6. You would be surprised to find out who else in your work environment is also part of the H6 community <3 If you have questions, feel free to leave comments below and I'll try my best to answer them.
Good luck to all H6s coming out of the work closet!
~when you are ready~
As always, “be well, do good work and keep in touch.” - Noam Chomsky